The present invention relates to a system and a method for controlling a vehicle during drive-off, and more particularly to a system and a method for controlling a clutch for driving the vehicle off in response to the operation of an accelerating member.
In the prior art there is known a control system for the operation of driving a vehicle off, wherein the relationship between a target position of the operation member of the clutch, for example, a release lever, and the amount of operation of an accelerator pedal is defined in advance and the semi-engaged state of the clutch is controlled in accordance with the relationship for driving the vehicle off.
For example, Japanese Patent Application Public Disclosure No. Sho 57-182530 corresponding to U.S. Pat. No. 4,488,625, discloses a conventional system of such type, in which the engaged condition of the clutch required at each instant is determined by the use of map data corresponding to a relationship of the type described above. In the conventional system the operation for engaging the clutch is ended even if the power output of the engine is insufficient for the engine load. This condition will be referred to as "power insufficiency" in this specification. The operation for engaging the clutch is restarted after the condition of power insufficiency has been overcome, whereby the occurrence of the engine failure at drive-off of the vehicle can be prevented.
However, according to the conventional system described above, the clutch operation for engagement is not carried out even if the driver depresses the acceleration pedal when power insufficiency has occurred, and after recovery from the state of power insufficiency the clutch may be operated by a stroke whose magnitude corresponds to the operation of the accelerator pedal effected during the state of power insufficiency. Consequently, in the case where power insufficiency has occurred, when the accelerator pedal is depressed and the degree of the depression thereof is maintained constant, the operation for clutch engagement is carried out with a time delay after recovery from power insufficiency no matter what constant level of depression of the accelerator pedal is maintained. This gives the driver an uncomfortable feeling.